Multi-radar, or more generally multi-sensor, data merging strategies are based on merging detection information generated by each sensor in a cartesian frame of reference common to all the sensors. In principle, these strategies take no account of the bistatic character of the measurements provided when one of these sensors is a passive radar. They thus correspond to sub-optimum merging solutions for this type of sensor.
Information delivered by different sensors may be merged either at the individual detection (merging of plots) level or at the tracking (merging of tracks) level. It is known that the first of these strategies is that which provides the better performance, at the cost of greater complexity than the second. Moreover, given that for a passive radar system to be able to deliver consistent cartesian tracks (i.e. tracks sufficiently pertinent to be merged with data coming from other sensors), it is necessary for the detected targets to be detected simultaneously at a plurality of the bistatic bases that constitute its configuration (ideally at least three bases), a track merging type approach runs the risk of proving detrimental.
It should further be noted that the formation of tracks in a passive radar system is preceded by various processing steps aiming in particular to associate with each other radar plots (i.e. detections) formed on the basis of a plurality of bistatic bases. Such a configuration thus offers possibilities, not yet exploited, of merging detection information coming from different types of sensors in a manner different from that generally employed. The present invention aims to define a merger scheme making best possible use of the tracking internal architecture of a passive radar to incorporate therein exogenous information (coming from other sensors) likely to improve tracking quality and/or to accelerate tracking.